Effect of extracorporeal membrane oxygenation on left ventricular function of swine

Aortic stenosis and mitral regurgitation modify the effect of venoarterial extracorporeal membrane oxygenation on left ventricular function in cardiogenic shock

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is widely used in the treatment of patients experiencing cardiogenic shock (CS). However, increased VA-ECMO blood flow (EBF) may significantly impair left ventricular (LV) performance. The objective of the present study was to assess the effect of VA-ECMO on LV function in acute CS with concomitant severe aortic stenosis (AS) or mitral regurgitation (MR) in a porcine model. Eight female swine (45 kg) underwent VA-ECMO implantation under general anaesthesia and mechanical ventilation. Acute CS was induced by global myocardial hypoxia. Subsequently, severe AS was simulated by obstruction of the aortic valve, while severe MR was induced by mechanical destruction of the mitral valve. Haemodynamic and LV performance variables were measured at different rates of EBF rates (ranging from 1 to 4 L/min), using arterial and venous catheters, a pulmonary artery catheter, and LV pressure-volume catheter. Data are expressed as median (interquartile range). Myocardial hypoxia resulted in declines in cardiac output to 2.7 (1.9-3.1) L/min and LV ejection fraction to 15.2% (10.5-19.3%). In severe AS, increasing EBF from 1 to 4 L/min was associated with a significant elevation in mean arterial pressure (MAP), from 33.5 (24.2-34.9) to 56.0 (51.9-73.3) mmHg (P ˂ 0.01). However, LV volumes (end-diastolic, end-systolic, stroke) remained unchanged, and LV end-diastolic pressure (LVEDP) significantly decreased from 24.9 (21.2-40.0) to 19.1 (15.2-29.0) mmHg (P ˂ 0.01). In severe MR, increasing EBF resulted in a significant elevation in MAP from 49.0 (28.0-53.4) to 72.5 (51.4-77.1) mmHg (P ˂ 0.01); LV volumes remained stable and LVEDP increased from 17.1 (13.7-19.1) to 20.8 (16.3-25.6) mmHg (P ˂ 0.01). Results of this study indicate that the presence of valvular heart disease may alleviate negative effect of VA-ECMO on LV performance in CS. Severe AS fully protected against LV overload, and partial protection was also detected with severe MR, although at the cost of increased LVEDP and, thus, higher risk for pulmonary oedema.

Hemodynamic adaptation of heart failure to percutaneous venoarterial extracorporeal circulatory supports

Extracorporeal life support (ECLS) is a treatment modality that provides prolonged blood circulation, gas exchange and can partially support or fully substitute functions of heart and lungs in patients with severe but potentially reversible cardiopulmonary failure refractory to conventional therapy. Due to high-volume bypass, the extracorporeal flow is interacting with native cardiac output. The pathophysiology of circulation and ECLS support reveals significant effects on arterial pressure waveforms, cardiac hemodynamics, and myocardial perfusion. Moreover, it is still subject of research, whether increasing stroke work caused by the extracorporeal flow is accompanied by adequate myocardial oxygen supply. The left ventricular (LV) pressure-volume mechanics are reflecting perfusion and loading conditions and these changes are dependent on the degree of the extracorporeal blood flow. By increasing the afterload, artificial circulation puts higher demands on heart work with increasing myocardial oxygen consumption. Further, this can lead to LV distention, pulmonary edema, and progression of heart failure. Multiple methods of LV decompression (atrial septostomy, active venting, intra-aortic balloon pump, pulsatility of flow) have been suggested to relieve LV overload but the main risk factors still remain unclear. In this context, it has been recommended to keep the rate of circulatory support as low as possible. Also, utilization of detailed hemodynamic monitoring has been suggested in order to avoid possible harm from excessive extracorporeal flow.

Advanced Pulmonary and Cardiac Support of COVID-19 Patients: Emerging Recommendations From ASAIO-A "Living Working Document"

The severe acute respiratory syndrome (SARS)-CoV-2 is an emerging viral pathogen responsible for the global coronavirus disease 2019 (COVID)-19 pandemic resulting in significant human morbidity and mortality. Based on preliminary clinical reports, hypoxic respiratory failure complicated by acute respiratory distress syndrome is the leading cause of death. Further, septic shock, late-onset cardiac dysfunction, and multiorgan system failure are also described as contributors to overall mortality. Although extracorporeal membrane oxygenation and other modalities of mechanical cardiopulmonary support are increasingly being utilized in the treatment of respiratory and circulatory failure refractory to conventional management, their role and efficacy as support modalities in the present pandemic are unclear. We review the rapidly changing epidemiology, pathophysiology, emerging therapy, and clinical outcomes of COVID-19; and based on these data and previous experience with artificial cardiopulmonary support strategies, particularly in the setting of infectious diseases, provide consensus recommendations from ASAIO. Of note, this is a "living document," which will be updated periodically, as additional information and understanding emerges.

Advanced Pulmonary and Cardiac Support of COVID-19 Patients: Emerging Recommendations From ASAIO-a Living Working Document

The severe acute respiratory syndrome-CoV-2 is an emerging viral pathogen responsible for the global coronavirus disease 2019 pandemic resulting in significant human morbidity and mortality. Based on preliminary clinical reports, hypoxic respiratory failure complicated by acute respiratory distress syndrome is the leading cause of death. Further, septic shock, late-onset cardiac dysfunction, and multiorgan system failure are also described as contributors to overall mortality. Although extracorporeal membrane oxygenation and other modalities of mechanical cardiopulmonary support are increasingly being utilized in the treatment of respiratory and circulatory failure refractory to conventional management, their role and efficacy as support modalities in the present pandemic are unclear. We review the rapidly changing epidemiology, pathophysiology, emerging therapy, and clinical outcomes of coronavirus disease 2019; and based on these data and previous experience with artificial cardiopulmonary support strategies, particularly in the setting of infectious diseases, provide consensus recommendations from American Society for Artificial Internal Organs. Of note, this is a living document, which will be updated periodically, as additional information and understanding emerges.

The Role of Echocardiography in Neonates and Pediatric Patients on Extracorporeal Membrane Oxygenation

Indications for extracorporeal membrane oxygenation (ECMO) and extracorporeal cardiopulmonary resuscitation (ECPR) are expanding, and echocardiography is a tool of utmost importance to assess safety, effectiveness and readiness for circuit initiation and separation. Echocardiography is key to anticipating complications and improving outcomes. Understanding the patient's as well as the ECMO circuit's anatomy and physiology is crucial prior to any ECMO echocardiographic evaluation. It is also vital to acknowledge that the utility of echocardiography in ECMO patients is not limited to the evaluation of cardiac function, and that clinical decisions should not be made exclusively upon echocardiographic findings. Though echocardiography has specific indications and applications, it also has limitations, characterized as: prior to and during cannulation, throughout the ECMO run, upon separation and after separation from the circuit. The use of specific and consistent echocardiographic protocols for patients on ECMO is recommended.

Electrocardiogram-synchronized pulsatile extracorporeal life support preserves left ventricular function and coronary flow in a porcine model of cardiogenic shock

Introduction

Veno-arterial extracorporeal life support (ECLS) is increasingly being used to treat rapidly progressing or severe cardiogenic shock. However, it has been repeatedly shown that increased afterload associated with ECLS significantly diminishes left ventricular (LV) performance. The objective of the present study was to compare LV function and coronary flow during standard continuous-flow ECLS support and electrocardiogram (ECG)-synchronized pulsatile ECLS flow in a porcine model of cardiogenic shock.

Methods

Sixteen female swine (mean body weight 45 kg) underwent ECLS implantation under general anesthesia and artificial ventilation. Subsequently, acute cardiogenic shock, with documented signs of tissue hypoperfusion, was induced by initiating global myocardial hypoxia. Hemodynamic cardiac performance variables and coronary flow were then measured at different rates of continuous or pulsatile ECLS flow (ranging from 1 L/min to 4 L/min) using arterial and venous catheters, a pulmonary artery catheter, an LV pressure-volume loop catheter, and a Doppler coronary guide-wire.

Results

Myocardial hypoxia resulted in declines in mean cardiac output to 1.7±0.7 L/min, systolic blood pressure to 64±22 mmHg, and LV ejection fraction (LVEF) to 22±7%. Synchronized pulsatile flow was associated with a significant reduction in LV end-systolic volume by 6.2 mL (6.7%), an increase in LV stroke volume by 5.0 mL (17.4%), higher LVEF by 4.5% (18.8% relative), cardiac output by 0.37 L/min (17.1%), and mean arterial pressure by 3.0 mmHg (5.5%) when compared with continuous ECLS flow at all ECLS flow rates (P<0.05). At selected ECLS flow rates, pulsatile flow also reduced LV end-diastolic pressure, end-diastolic volume, and systolic pressure. ECG-synchronized pulsatile flow was also associated with significantly increased (7% to 22%) coronary flow at all ECLS flow rates.

Conclusion

ECG-synchronized pulsatile ECLS flow preserved LV function and coronary flow compared with standard continuous-flow ECLS in a porcine model of cardiogenic shock.

Tachycardia-Induced Cardiomyopathy As a Chronic Heart Failure Model in Swine

A stable and reliable model of chronic heart failure is required for many experiments to understand hemodynamics or to test effects of new treatment methods. Here, we present such a model by tachycardia-induced cardiomyopathy, which can be produced by rapid cardiac pacing in swine. A single pacing lead is introduced transvenously into fully anaesthetized healthy swine, to the apex of the right ventricle, and fixated. Its other end is then tunneled dorsally to the paravertebral region. There, it is connected to an in-house modified heart pacemaker unit that is then implanted in a subcutaneous pocket. After 4 - 8 weeks of rapid ventricular pacing at rates of 200 - 240 beats/min, physical examination revealed signs of severe heart failure - tachypnea, spontaneous sinus tachycardia, and fatigue. Echocardiography and X-ray showed dilation of all heart chambers, effusions, and severe systolic dysfunction. These findings correspond well to decompensated dilated cardiomyopathy and are also preserved after the cessation of pacing. This model of tachycardia-induced cardiomyopathy can be used for studying the pathophysiology of progressive chronic heart failure, especially hemodynamic changes caused by new treatment modalities like mechanical circulatory supports. This methodology is easy to perform and the results are robust and reproducible.

Regional Tissue Oximetry Reflects Changes in Arterial Flow in Porcine Chronic Heart Failure Treated With Venoarterial Extracorporeal Membrane Oxygenation

Venoarterial extracorporeal membrane oxygenation (VA ECMO) is widely used in treatment of decompensated heart failure. Our aim was to investigate its effects on regional perfusion and tissue oxygenation with respect to extracorporeal blood flow (EBF). In five swine, decompensated low-output chronic heart failure was induced by long-term rapid ventricular pacing. Subsequently, VA ECMO was introduced and left ventricular (LV) volume, aortic blood pressure, regional arterial flow and tissue oxygenation were continuously recorded at different levels of EBF. With increasing EBF from minimal to 5 l/min, mean arterial pressure increased from 47±22 to 84±12 mm Hg (P<0.001) and arterial blood flow increased in carotid artery from 211±72 to 479±58 ml/min (P<0.01) and in subclavian artery from 103±49 to 296±54 ml/min (P<0.001). Corresponding brain and brachial tissue oxygenation increased promptly from 57±6 to 74±3 % and from 37±6 to 77±6 %, respectively (both P<0.01). Presented results confirm that VA ECMO is a capable form of heart support. Regional arterial flow and tissue oxygenation suggest that partial circulatory support may be sufficient to supply brain and peripheral tissue by oxygen.

Successful ECMO-cardiopulmonary resuscitation with the associated post-arrest cardiac dysfunction as demonstrated by MRI

Background

Veno-arterial extracorporeal membrane oxygenation (ECMO-CPR) is a life-saving rescue for selected patients when standard cardiopulmonary resuscitation fails. The use is increasing although the treatment modality is not fully established. Resuscitated patients typically develop a detrimental early post-arrest cardiac dysfunction that also deserves main emphasis. The present study investigates an ECMO-CPR strategy in pigs and assesses early post-arrest left ventricular function in detail. We hypothesised that a significant dysfunction could be demonstrated with this model using magnetic resonance imaging (MRI), not previously used early post-arrest.

Methods

In eight anaesthetised pigs, a 15-min ventricular fibrillation was resuscitated by an ECMO-CPR strategy of 150-min veno-arterial ECMO aiming at high blood flow rate and pharmacologically sustained aortic blood pressure and pulse pressure of 50 and 15 mmHg, respectively. Pre-arrest cardiac MRI and haemodynamic measurements of left ventricular function were compared to measurements performed 300-min post-arrest.

Results

All animals were successfully resuscitated, weaned from the ECMO circuit, and haemodynamically stabilised post-arrest. Cardiac output was maintained by an increased heart rate post-arrest, but left ventricular ejection fraction and stroke volume were decreased by approximately 50 %. Systolic circumferential strain and mitral annular plane systolic excursion as well as the left ventricular wall thickening were reduced by approximately 50–70 % post-arrest. The diastolic function variables measured were unchanged.

Conclusions

The present animal study demonstrates a successful ECMO-CPR strategy resuscitating long-lasting cardiac arrest with adequate post-arrest haemodynamic stability. The associated severe systolic left ventricular dysfunction could be charted in detail by MRI, a valuable tool for future cardiac outcome assessments in resuscitation research.

Trial registration

Institutional protocol number: FOTS 4611/13.

Electronic supplementary material

The online version of this article (doi:10.1186/s40635-015-0061-2) contains supplementary material, which is available to authorized users.

Increasing venoarterial extracorporeal membrane oxygenation flow negatively affects left ventricular performance in a porcine model of cardiogenic shock

Background

The aim of this study was to assess the relationship between extracorporeal blood flow (EBF) and left ventricular (LV) performance during venoarterial extracorporeal membrane oxygenation (VA ECMO) therapy.

Methods

Five swine (body weight 45 kg) underwent VA ECMO implantation under general anesthesia and artificial ventilation. Subsequently, acute cardiogenic shock with signs of tissue hypoxia was induced. Hemodynamic and cardiac performance parameters were then measured at different levels of EBF (ranging from 1 to 5 L/min) using arterial and venous catheters, a pulmonary artery catheter and a pressure–volume loop catheter introduced into the left ventricle.

Results

Myocardial hypoxia resulted in a decline in mean (±SEM) cardiac output to 2.8 ± 0.3 L/min and systolic blood pressure (SBP) to 60 ± 7 mmHg. With an increase in EBF from 1 to 5 L/min, SBP increased to 97 ± 8 mmHg (P < 0.001); however, increasing EBF from 1 to 5 L/min significantly negatively influences several cardiac performance parameters: cardiac output decreased form 2.8 ± 0.3 L/min to 1.86 ± 0.53 L/min (P < 0.001), LV end-systolic volume increased from 64 ± 11 mL to 83 ± 14 mL (P < 0.001), LV stroke volume decreased from 48 ± 9 mL to 40 ± 8 mL (P = 0.045), LV ejection fraction decreased from 43 ± 3 % to 32 ± 3 % (P < 0.001) and stroke work increased from 2096 ± 342 mmHg mL to 3031 ± 404 mmHg mL (P < 0.001). LV end-diastolic pressure and volume were not significantly affected.

Conclusions

The results of the present study indicate that higher levels of VA ECMO blood flow in cardiogenic shock may negatively affect LV function. Therefore, it appears that to mitigate negative effects on LV function, optimal VA ECMO blood flow should be set as low as possible to allow adequate tissue perfusion.

Left anterior descending coronary artery blood flow and left ventricular unloading during extracorporeal membrane oxygenation support in a swine model of acute cardiogenic shock

The impact of extracorporeal membrane oxygenation (ECMO) support on coronary blood flow and left ventricular unloading is still debated. This study aimed to further characterize the influence of ECMO on coronary artery blood flow and its ability to unload the left ventricle in a short-term model of acute cardiogenic shock. Seven anesthetized pigs were intubated and then underwent median sternotomy and cannulation for venoarterial (VA) ECMO. Flow in the left anterior descending (LAD) artery, left atrial pressure (LAP), left ventricular end-diastolic pressure (LVEDP), and mean arterial pressure (MAP) were measured before and after esmolol-induced cardiac dysfunction and after initiating VA-ECMO support. Induction of acute cardiogenic shock was associated with short-term increases in LAP from 8 ± 4 mm Hg to 18 ± 14 mm Hg (P = 0.9) and LVEDP from 5 ± 2 mm Hg to 13 ± 17 mm Hg (P = 0.9), and a decrease in MAP from 63 ± 16 mm Hg to 50 ± 24 mm Hg (P = 0.3). With VA-ECMO support, blood flow in the LAD increased from 28 ± 25 mL/min during acute unsupported cardiogenic shock to 67 ± 50 mL/min (P = 0.003), and LAP and LVEDP decreased to 8 + 5 mm Hg (P = 0.7) and 5 ± 3 mm Hg (P = 0.5), respectively. In this swine model of acute cardiogenic shock, VA-ECMO improved coronary blood flow and provided some degree of left ventricular unloading for the short duration of the study.

Coronary versus carotid blood flow and coronary perfusion pressure in a pig model of prolonged cardiac arrest treated by different modes of venoarterial ECMO and intraaortic balloon counterpulsation

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is increasingly used in cardiac arrest (CA). Adequacy of carotid and coronary blood flows (CaBF, CoBF) and coronary perfusion pressure (CoPP) in ECMO treated CA is not well established. This study compares femoro-femoral (FF) to femoro-subclavian (FS) ECMO and intraaortic balloon counterpulsation (IABP) contribution based on CaBF, CoBF, CoPP, myocardial and brain oxygenation in experimental CA managed by ECMO.

METHODS

In 11 female pigs (50.3 ± 3.4 kg), CA was randomly treated by FF versus FS ECMO ± IABP. Animals under general anesthesia had undergone 15 minutes of ventricular fibrillation (VF) with ECMO flow of 5 to 10 mL/kg/min simulating low-flow CA followed by continued VF with ECMO flow of 100 mL/kg/min. CaBF and CoBF were measured by a Doppler flow wire, cerebral and peripheral oxygenation by near infrared spectroscopy. CoPP, myocardial oxygen metabolism and resuscitability were determined.

RESULTS

CaBF reached values > 80% of baseline in all regimens. CoBF > 80% was reached only by the FF ECMO, 90.0% (66.1, 98.6). Addition of IABP to FF ECMO decreased CoBF to 60.7% (55.1, 86.2) of baseline, P = 0.004. FS ECMO produced 70.0% (49.1, 113.2) of baseline CoBF, significantly lower than FF, P = 0.039. Addition of IABP to FS did not change the CoBF; however, it provided significantly higher flow, 76.7% (71.9, 111.2) of baseline, compared to FF + IABP, P = 0.026. Both brain and peripheral regional oxygen saturations decreased after induction of CA to 23% (15.0, 32.3) and 34% (23.5, 34.0), respectively, and normalized after ECMO institution. For brain saturations, all regimens reached values exceeding 80% of baseline, none of the comparisons between respective treatment approaches differed significantly. After a decline to 15 mmHg (9.5, 20.8) during CA, CoPP gradually rose with time to 68 mmHg (43.3, 84.0), P = 0 .003, with best recovery on FF ECMO. Resuscitability of the animals was high, both 5 and 60 minutes return of spontaneous circulation occured in eight animals (73%).

CONCLUSIONS

In a pig model of CA, both FF and FS ECMO assure adequate brain perfusion and oxygenation. FF ECMO offers better CoBF than FS ECMO. Addition of IABP to FF ECMO worsens CoBF. FF ECMO, more than FS ECMO, increases CoPP over time.

Myocardial oxidative metabolism and protein synthesis during mechanical circulatory support by extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) provides essential mechanical circulatory support necessary for survival in infants and children with acute cardiac decompensation. However, ECMO also causes metabolic disturbances, which contribute to total body wasting and protein loss. Cardiac stunning can also occur, which prevents ECMO weaning, and contributes to high mortality. The heart may specifically undergo metabolic impairments, which influence functional recovery. We tested the hypothesis that ECMO alters oxidative metabolism and protein synthesis. We focused on the amino acid leucine and integration with myocardial protein synthesis. We used a translational immature swine model in which we assessed in heart 1) the fractional contribution of leucine (FcLeucine) and pyruvate to mitochondrial acetyl-CoA formation by nuclear magnetic resonance and 2) global protein fractional synthesis (FSR) by gas chromatography-mass spectrometry. Immature mixed breed Yorkshire male piglets (n = 22) were divided into four groups based on loading status (8 h of normal circulation or ECMO) and intracoronary infusion [(13)C(6),(15)N]-L-leucine (3.7 mM) alone or with [2-(13)C]-pyruvate (7.4 mM). ECMO decreased pulse pressure and correspondingly lowered myocardial oxygen consumption (∼40%, n = 5), indicating decreased overall mitochondrial oxidative metabolism. However, FcLeucine was maintained and myocardial protein FSR was marginally increased. Pyruvate addition decreased tissue leucine enrichment, FcLeucine, and Fc for endogenous substrates as well as protein FSR. The heart under ECMO shows reduced oxidative metabolism of substrates, including amino acids, while maintaining 1) metabolic flexibility indicated by ability to respond to pyruvate and 2) a normal or increased capacity for global protein synthesis.

Extracorporeal membrane oxygenation induced cardiac dysfunction in newborn lambs

Extracorporeal membrane oxygenation (ECMO) is routinely used to support cardiopulmonary failure in infants and children. Suboptimal outcomes for primary cardiac support suggest a need for investigation of the impact of ECMO on the heart. Twenty-four newborn lambs received a brief period of ECMO support to investigate the hypothesis that ECMO produces cardiac dysfunction in newborn lamb. Dorset newborn lambs, 4-7 days of age, were exposed to ECMO for 5 min at a 100 ml/kg flow rate and quickly weaned off. Measurements included echocardiographic mean left ventricular (LV) velocity of circumferential fiber shortening corrected for heart rate (mVCFc), LV shortening fraction, and peak systolic wall stress plus hemodynamic measurement of LV maximum rate of pressure change with time (LV dp/dt max), maximum rate of pressure change divided by developed pressure (LV dp/dtP), right atrial pressure, pulmonary capillary wedge pressure, mean pulmonary artery pressure, LV peak and end-diastolic pressure, and aortic pressure. These measures were also obtained after an exposure to 5 min of ECMO and immediate disconnect for 5 min, followed by ECMO administration for 1 h again, followed by discontinuation of ECMO. LV mVCFc is decreased after exposure to 5 min of ECMO support despite a decrease in LV peak systolic wall stress that provides afterload reduction. LV mVCFc is inversely related to peak systolic wall stress at a significance level of p < 0.0001. The time period after initiation of ECMO is a significant factor in the model (p = 0.0097). Time [baseline] was different from the other time points with p = 0.0010. Average mVCFc at baseline is 1.27 ± 0.35 and decreases to 1.01 ± 0.42 after 5 min of ECMO that is then withdrawn. Peak systolic wall stress decreases from 36.0 ± 13.1 at baseline to 29.8 ± 12.1 after 5 min of ECMO. LV dp/dt max decreases from 1,769 ± 453 mmHg/s at baseline to 1,311 ± 513 mmHg/s after exposure to 5 min of ECMO (p = 0.0005). Baseline LV dp/dt max is different from each point after start of ECMO. Diastolic LVdp/dt min increased from -1,340 ± 477 mmHg/s to -908 ± 393 mmHg/s at 5 min. Echocardiographic mVCFc, when considered in isolation or as a function of LV peak systolic wall stress, shows diminished LV function after ECMO. Hemodynamic measurement of LV dp/dt max and LV dp/dt min confirms the observation. Separation of the humoral from mechanical effect of ECMO with the short exposure to the extracorporeal circuit shows that an immediate decrement of LV function occurs at initiation of ECMO, a finding that has not been stressed with previous studies of extracorporeal support. This implies a potentially outcome-limiting deleterious effect for the patient who requires ECMO support for the heart rather than the lungs. We should continue to strive to understand and ameliorate this deleterious effect of the extracorporeal circulation circuit.

ECMO cannulation controversies and complications

Advances in extracorporeal life support have expanded indications for use extending beyond patients undergoing cardiac surgery. The approach to cannulation in patients requiring extracorporeal membrane oxygenation should be individualized and based on the specific clinical scenario in which the need arises. Adherence to proper techniques of vessel visualization, exposure, and cannulation along with accurate placement of cannulae will optimize flows and minimize complications in this setting. Patients in need of mechanical circulatory support require input from a multidisciplinary team approach with systematic clinical evaluation to optimize outcome. If hemodynamics do not initially permit the successful separation from mechanical support, then a systematic search for potentially reversible patient and/ or pump related factors should be undertaken. The success of this therapy is predicated on patient selection, a multidisciplinary team approach in the intensive care unit, adherence to precise technical principles, and repeated patient evaluation.

Mechanical cardiac support in the young. Short-term support: ECMO

Although based on technology developed several decades ago, extracorporeal membrane oxygenation (ECMO) retains great clinical relevance in the management of advanced pediatric cardiorespiratory disease. Largely because of its widespread use in pediatric patients with respiratory failure, familiarity with this technology has established ECMO as the most commonly used form of mechanical circulatory support in children. Clinical applications and technical aspects of ECMO support continue to evolve, ensuring the ongoing importance of this modality for pediatric circulatory support.

Mechanical circulatory support for infants and children with cardiac disease

Mechanical circulatory support is assuming an expanding role in the practice of congenital cardiac surgery. Extracorporeal membrane oxygenation and centrifugal ventricular assist devices are still the mainstay of mechanical circulatory support for children; however, newly developed pulsatile, paracorporeal ventricular assist devices designed for pediatric applications are achieving increased utilization. In addition, several new, continuous flow devices that are under development as fully implantable systems for adults, ultimately may be useful for pediatric patients.